NEW YORK — Mothers deciding to place their infants for adoption deserve better counseling, more time to change their minds, and more support in trying to keep track of the children they relinquish, a leading adoption institute recommends in a sweeping new report.

The Evan B. Donaldson Adoption Institute said its report, issued today, is the most comprehensive ever devoted to birth mothers, whom it described as “the least understood and most stigmatized participants” in the adoption process.

“Birth parents have been a population that has been neglected for so long — just starting a dialogue that respects them as flesh-and-blood human beings is really important,” said the institute’s executive director, Adam Pertman.

The report focuses on U.S. mothers who voluntarily place infants for adoption — an estimated 13,000 to 14,000 such adoptions occur annually. Most of this country’s roughly 135,000 adoptions each year are from foster care; the next biggest category is overseas adoptions.

In contrast to a few decades ago, many of the voluntary U.S. adoptions are “open” — with adoptive parents communicating with the birth mother and often allowing her regular contact with the adopted child. However, the report says a significant number of birth mothers are manipulated, pressured and deceived — sometimes finding that they have no recourse when agreements they negotiated to visit or keep track of their children are broken.

“If you make a decision about adoption based on thinking you’ll be able to see this child grow up, and suddenly the carpet is pulled from under you and the family moves away without giving you their address, you go through this traumatic loss that some women never come to terms with,” the report’s author, Susan Smith, said in a telephone interview.

The report recommends that all states establish legally enforceable post-adoption contact agreements; it said only 13 now have such policies covering infant adoptions.

It also recommended extending other rights to birth mothers, including pre-adoption access to pressure-free counseling about their options.

“It amazes me how many adoptions are done by attorneys, where the birth mothers have zero counseling,” Smith said. “There are a lot of sharks out there, manipulating them in every way they know how, and the laws don’t prevent that in most states.”

Jenna Hatfield, 25, of Cambridge, Ohio, said she got little insightful counseling before she agreed three years ago to the adoption of her daughter, Ariana, by a couple from Pennsylvania.

“My agency did not tell me until a month after I signed the agreement that open adoptions are not enforceable in Pennsylvania,” Hatfield said.

She said she has been fortunate in befriending the adoptive parents; they regularly bring Ariana to visit Hatfield, who is now married and has a 1-year-old son.

“Thus far it’s worked very well for me — just a couple of bumps,” Hatfield said. “But unless both sides are willing to put in the legwork, there are going to be problems, and they’d need counseling to help them meet in the middle.”

One problem cited in the report is a shortage of mental health professionals trained to understand the grief and loss experienced by birth mothers.

The report said birth mothers’ chances of achieving peace of mind are greatest if they are able to keep in contact with the adopted children, or get continuing information about them.

“Mothers after childbirth are in a very vulnerable state,” Smith said. “We need laws and practices that protect their rights and interests.”

The report recommended that birth mothers be given at least a few weeks after childbirth before the adoption decision becomes irrevocable. At present, irrevocable consent for an adoption can be established within four days after birth in roughly half the states.

“In many states, you can change your mind about buying a vacuum cleaner or taking out a mortgage within a prescribed time period, but most states do not have a revocation period during which a mother can change her mind about relinquishing her child,” the report said.

The report said the rights of birth fathers also deserve stronger protections, including notification of pending adoptions.

Adoption practices, the report said, “are too often based on outdated understandings, faulty stereotypes, and misinformation from the time that secrecy pervaded the adoption world.”